1. Field of the Invention
The invention relates to a terminal fitting and a connector.
2. Description of the Related Art
U.S. Pat. No. 6,659,811 discloses a waterproof connector with a housing that has a cavity. The connector also has a terminal fitting and a rubber plug that are fixed to an end of an insulated wire. The rubber plug is fit into the entrance of the cavity for sealing as the terminal fitting is retained and accommodated in the cavity.
The terminal fitting has a rectangular tubular main body with a connecting portion for connecting to a mating terminal. A wire barrel and an insulation barrel are provided behind the terminal main body. Insulating coating is stripped off an end of the insulated wire to expose an end of a core. A mounting tube projecting from the front surface of the rubber plug is fit on the outer circumferential surface of the end of the remaining insulating coating. The wire barrel then is crimped into connection with the end of the core and the insulation barrel is crimped to the end of the insulating coating and to the mounting tube of the rubber plug on the end of the insulating coating. The terminal fitting that has been fixed to the insulated wire and the rubber plug is inserted into a corresponding cavity of the housing from behind and is locked primarily by a resin locking lance in the cavity. A retainer assembled into the housing while projecting down from a ceiling of the cavity is engaged with an upper part of a rear end of the terminal main body to lock the terminal fitting redundantly.
Insulated wires have been made thinner, for example, to reduce the weight of a wiring harness. However, the thinning of the wires may lead to fractures due to a reduction in wire strength and the like. This is particularly notable in a wire having the terminal fitting and a rubber plug fixed to the end, as described above. More particularly, the wire barrel is crimped directly to the end of the core of such a wire to exhibit a large fixing force, whereas the insulation barrel is crimped to the end of the insulating coating via the mounting tube of the rubber plug to exhibit a small fixing force. Thus, the core may elongate, while the insulating coating with a small fixing force scrapes through and slips out from the insulation barrel and accordingly the core may break, for example, when the insulated wire is pulled strongly backward. The rubber plug also may scrape through and slip out from the entrance of the cavity together with the insulated wire.
A three-barrel terminal fitting has been proposed to address the above-described problems. The three-barrel terminal fitting has an insulation barrel crimped directly to an end of an insulating coating to increase a fixing force of an insulated wire. A rubber plug barrel also is proposed for crimped connection to the rubber plug. However, a long area is necessary for three barrels. A considerable shape change of a housing, such as a change in the length of the cavity, is necessitated if the entire length of the terminal fitting is extended for this purpose. The foremost wire barrel must be closer to the terminal main body if the entire length of the terminal fitting is assumed to remain unchanged, and this more forward wire barrel may interfere with a retainer to be inserted to a position behind the terminal main body for doubly locking the terminal fitting. A differently configured retainer may be necessary to avoid interference. The front end of the wire barrel could be retracted to avoid interference with the retainer. However, the retracted wire barrel is smaller and may not achieve sufficient contact performance. Hence, the above-described problem cannot be dealt with easily.
The invention was developed in view of the above situation and an object thereof is to provide a terminal fitting which exhibits a good tensile strength when an insulated wire is pulled and can be used without changing the design of an existing housing, and a connector using this terminal fitting as well as an assembling method therefor.